U.S. patent application number 11/079989 was filed with the patent office on 2006-08-31 for keyboard structure.
This patent application is currently assigned to Nokia Corporation. Invention is credited to Marko Tuhkala.
Application Number | 20060191780 11/079989 |
Document ID | / |
Family ID | 36117653 |
Filed Date | 2006-08-31 |
United States Patent
Application |
20060191780 |
Kind Code |
A1 |
Tuhkala; Marko |
August 31, 2006 |
KEYBOARD STRUCTURE
Abstract
A keyboard is disclosed comprising a rigid base member including
at least a first surface; the base member including electrical
circuitry structures, which structures define a plurality of
connection zones on the first surface; the first surface of the
base member including a plurality of grooves in order to connect at
least some connection zones; a plurality of flexible, resilient
domes covering said base member and being aligned with the
connection zones on the first surface of the base member; the
underside of each of said domes including a conductive surface that
is capable of completing an electrical connection at said
connection zone when said dome is deflected downwardly against said
circuitry structures; wherein each connection zone communicates
with at least one of said grooves in such a manner that the air
present under said dome is forced into one of said grooves when
said dome is deflected downwardly.
Inventors: |
Tuhkala; Marko; (Kangasala,
FI) |
Correspondence
Address: |
WARE FRESSOLA VAN DER SLUYS &ADOLPHSON, LLP
BRADFORD GREEN, BUILDING 5
755 MAIN STREET, P O BOX 224
MONROE
CT
06468
US
|
Assignee: |
Nokia Corporation
|
Family ID: |
36117653 |
Appl. No.: |
11/079989 |
Filed: |
February 25, 2005 |
Current U.S.
Class: |
200/515 |
Current CPC
Class: |
H01H 13/88 20130101;
H01H 13/82 20130101; H01H 2213/01 20130101; H01H 2229/002 20130101;
H01H 13/702 20130101; H01H 2229/016 20130101 |
Class at
Publication: |
200/515 |
International
Class: |
H01H 1/10 20060101
H01H001/10 |
Claims
1. Keyboard comprising a substantially rigid base member including
a first surface; at least a first layer being part of electrical
circuitry structures and arranged on the first surface; the first
layer defining at least two individual key locations, each arranged
with a connection zone; a sheet covering said base member and with
at least two resilient key domes in alignment with the individual
connection zones of the at least two key locations; at least one
groove arranged in the first layer and extending between the at
least two individual key locations, said groove forming, together
with the sheet, a closed tunnel between said at least two
individual key locations, providing air ventilation between said at
least two key domes.
2. The keyboard according to claim 1, wherein the first layer is a
conductive layer and the at least one groove is arranged at least
partly in the conductive layer.
3. The keyboard according to claim 1, wherein the first layer is a
coating layer and the at least one groove is arranged at least
partly in the coating layer.
4. The keyboard according to claim 1, wherein the first layer is a
solder mask layer and the at least one groove is arranged at least
partly in the solder mask layer.
5. The keyboard according to claim 1, wherein the base member also
comprises a second layer of conductive material and the at least
one groove is arranged at least partly in said second layer.
6. The keyboard according to claim 1, wherein the base member also
comprises a second layer of dielectric material and the at least
one groove is arranged at least partly in said second layer.
7. The keyboard according to claim 1, wherein an underside of each
of said domes includes a conductive surface that is capable of
completing an electrical connection at said connection zone when
said dome is deflected downwardly against said circuitry
structures;
8. Mobile device comprising a keyboard, which keyboard comprises a
substantially rigid base member including a first surface; at least
a first layer being part of electrical circuitry structures and
arranged on the first surface; the first layer defining at least
two individual key locations, each arranged with a connection zone;
a sheet covering said base member and with at least two resilient
key domes in alignment with the individual connection zones of the
at least two key locations; at least one groove arranged in the
first layer and extending between the at least two individual key
locations, said groove forming, together with the sheet, a closed
tunnel between said at least two individual key locations,
providing air ventilation between said at least two key domes.
9. Method of use of a keyboard, which keyboard comprises a
substantially rigid base member including a first surface; at least
a first layer being part of electrical circuitry structures and
arranged on the first surface; the first layer defining at least
two individual key locations, each arranged with a connection zone;
a sheet covering said base member and with at least two resilient
key domes in alignment with the individual connection zones of the
at least two key locations; at least one groove arranged in the
first layer and extending between the at least two individual key
locations, said groove forming, together with the sheet, a closed
tunnel between said at least two individual key locations,
providing air ventilation between said at least two key domes; said
method comprising: deflecting one of said domes downwardly, and
directing air away from under said dome by means of said at least
one groove.
10. The method according to claim 9, wherein air is directed from
the downwardly deflected dome to another one of said domes.
11. Method for manufacturing air tunnels of a keyboard, which
keyboard comprises a substantially rigid base member including a
first surface; at least a first layer being part of electrical
circuitry structures and arranged on the first surface; the first
layer defining at least two individual key locations, each arranged
with a connection zone; a sheet covering said base member and with
at least two resilient key domes in alignment with the individual
connection zones of the at least two key locations; at least one
groove arranged in the first layer and extending between the at
least two individual key locations, said groove forming, together
with the sheet, a closed tunnel between said at least two
individual key locations, providing air ventilation between said at
least two key domes; wherein the at least one groove is formed in
the first layer during circuit board processing.
12. The method according to claim 11, wherein the at least one
groove is formed by etching.
13. The method according to claim 11, wherein the first layer is a
conductive layer and the at least one groove is arranged at least
partly in the conductive layer.
14. The method according to claim 11, wherein the first layer is a
coating layer and the at least one groove is formed at least partly
in the coating layer.
15. The method according to claim 11, wherein the first layer is a
solder mask layer and the at least one groove is formed at least
partly in the solder mask layer.
16. The method according to claim 11, wherein the first layer is a
layer of conductive material and the at least one groove is formed
at least partly in said layer.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a keyboard, a mobile device, a
method for use in a keyboard and a method for manufacturing a
keyboard.
BACKGROUND OF THE INVENTION
[0002] There are many types of keyboard systems in use in various
types of electronic devices, such as mobile devices. Some of these
keyboard systems involve the use of a dome sheet structure over a
printed circuit board.
[0003] The dome sheet typically includes a plurality of domes in a
predetermined pattern, which is aligned with a pattern of switch
locations on the printed circuitry. When a dome is depressed or
collapsed by finger pressure, it causes a corresponding connection
to be made in the underlying switch in the printed circuitry. This
may be affected by finger pressure directly on the dome or
indirectly by finger pressure on a key positioned over the
dome.
[0004] When the components are clamped together or bonded during
manufacturing, air is trapped under each dome. This air must be
vented in some manner to enable the dome to be depressed or
collapsed in a controlled and smooth manner when pressing a key.
Venting is also required to allow the air pressure to equalize in
changing atmosphere situations. Venting prevents mushiness and
improves the tactile feel of a key when it is depressed.
[0005] Some previous keyboards of this type have included a spacer
sheet between the dome sheet and the printed circuitry. A series of
slots have been die cut in the spacer sheet to allow air to be
forced out from under a dome when the dome is depressed or
collapsed.
[0006] However, on a large multi-keyed keyboard, the presence of
numerous slots causes the spacer sheet to be unsteady and difficult
to handle and assemble with the other components during
manufacturing. Also the use of a separate spacer sheet is
disadvantageous in many manufacturing and assembling processes.
[0007] Patent publication U.S. Pat. No. 6,491,456 describes a key
signal-generating device, which has a thin film circuit board to
generate key signals and a plurality of hollow rubber domes set on
the thin film circuit board, which domes are compressed by their
corresponding keys to activate the thin film circuit board to
generate corresponding signals. The rubber domes have a
predetermined space that is filled with air. The thin film circuit
board has a top surface and a trench on the top surface. One end of
the trench extends into the predetermined space so that the
predetermined space is in communication with the atmosphere. When a
key is pressed, the corresponding rubber dome is squeezed by the
key, causing the air in the predetermined space to exit out to the
atmosphere through the trench. This kind of a structure causes a
dust problem between key dome and circuit board in continuous use,
especially when the keyboard is in a mobile device.
[0008] Patent publication EP 0 322 515 A describes a keyboard
structure (e.g. for a calculator), which includes a base member
having a plurality of channels or a chamber, circuitry defining a
plurality of switches in a pattern, and optionally a plurality of
domes in registry with the switch sites. The dome sheet is arranged
over a printed circuit board, which is in turn supported or carried
on the relatively rigid base member. When a dome is depressed or
deflected downwardly, the air under the dome passes into a channel
or a chamber where it is distributed away from the switch site. A
vent aperture communicating between the channel or chamber and the
atmosphere may also be included. In this structure there is no dust
problem, but this kind of a keyboard is rather complex when
considering the required manufacturing process.
SUMMARY OF THE INVENTION
[0009] Now, a solution has been invented, which represents an
improvement in venting techniques in a keyboard, such as is used in
a mobile device, for example.
[0010] To attain this purpose, the keyboard comprises a
substantially rigid base member including a first surface; at least
a first layer being part of the electrical circuitry structures and
arranged on the first surface; the first layer defining at least
two individual key locations, each arranged with a connection zone;
a sheet covering said base member and with at least two resilient
key domes arranged to be aligned with the individual connection
zones of the at least two key locations; at least one groove
arranged in the first layer and extending between the at least two
key locations, said groove forming, together with the sheet, a
closed tunnel between said at least two key locations, providing
air ventilation between said at least two key domes.
[0011] The invention further relates to a mobile device comprising
a keyboard, which keyboard comprises a substantially rigid base
member including a first surface; at least a first layer being part
of the electrical circuitry structures and arranged on the first
surface; the first layer defining at least two individual key
locations, each arranged with a connection zone; a sheet covering
said base member and with at least two resilient key domes arranged
to be aligned with the individual connection zones of the at least
two key locations; at least one groove arranged in the first layer
and extending between the at least two key locations, said groove
forming, together with the sheet, a closed tunnel between said at
least two key locations, providing air ventilation between said at
least two key domes.
[0012] In addition, the invention relates to a method of use of a
keyboard, which keyboard comprises a substantially rigid base
member including a first surface; at least a first layer being part
of the electrical circuitry structures and arranged on the first
surface; the first layer defining at least two individual key
locations, each arranged with a connection zone; a sheet covering
said base member and with at least two resilient key domes arranged
to be aligned with the individual connection zones of the at least
two key locations; at least one groove arranged in the first layer
and extending between the at least two key locations, said groove
forming, together with the sheet, a closed tunnel between said at
least two key locations, providing air ventilation between said at
least two key domes; in which method air is directed away from
under the dome by means of said grooves when said dome is deflected
downwardly.
[0013] The invention further relates to a method for manufacturing
air tunnels of a keyboard, which keyboard comprises a substantially
rigid base member including a first surface; at least a first layer
being part of the electrical circuitry structures and arranged on
the first surface; the first layer defining at least two individual
key locations, each arranged with a connection zone; a sheet
covering said base member and with at least two resilient key domes
arranged to be aligned with the individual connection zones of the
at least two key locations; at least one groove arranged in the
first layer and extending between the at least two key locations,
said groove forming, together with the sheet, a closed tunnel
between said at least two key locations, providing air ventilation
between said at least two key domes; wherein the grooves are formed
in the first layer during circuit board processing.
[0014] In one embodiment the air tunnels will be made into a base
member of the keyboard (for example a printed circuit board or a
printed wiring board) by leaving a soldering mask open from the
tunnel position. In another embodiment the air tunnels are
increased by also leaving copper and/or one layer open from the
tunnel position. In this manner it is possible to get the running
change into use faster.
[0015] In another embodiment air is directed from the downward
deflected dome to other domes.
[0016] The different embodiments of the invention offer several
advantages over solutions of prior art. Depending on the
implementation manner of the embodiment, the invention may provide,
for example, one or more of the following advantages: [0017] in
many solutions the keyboard according to the present invention is
cheaper to manufacture because it has a small number of separate
components or layers [0018] it is faster to implement into
practical devices than known structures [0019] it is a cheaper way
to implement closed air tunnels than the known structures [0020]
the dust problem between the key dome and the base can be avoided
because the air tunnels are not open to atmosphere and the air
communicates in a closed space between the domes [0021] the
functionality of the keyboard remains the same as with more
expensive structures [0022] the keyboard can be designed to be thin
to suit modern small sized mobile devices
[0023] An important benefit of the invention is that the air
tunnels can now in most cases be made with a normal printed circuit
board or a printed wiring board process, which means that no extra
manufacturing phases need to be introduced.
DESCRIPTION OF THE DRAWINGS
[0024] In the following, the invention will be described in more
detail with reference to the appended principle drawings, in
which
[0025] FIG. 1 shows a base member according to the invention in a
front view
[0026] FIG. 2 shows the embodiment according to FIG. 1 with a dome
sheet in a side view
[0027] FIG. 3 shows another embodiment in a side view
[0028] FIG. 4 shows some air flows in the keyboard according to
FIG. 3
[0029] FIG. 5 shows a mobile device.
[0030] For the sake of clarity, the figures only show the details
necessary for understanding the invention. The structures and
details, which are not necessary for understanding the invention
and which should be evident to anyone skilled in the art, have been
omitted from the figures in order to emphasize the essential
characteristics of the invention.
[0031] In addition, the dimensions and scale of the figures are not
necessarily correct. The dimensions in the figures have been
selected only in order to emphasize the essential characteristics
of the invention.
[0032] Now, the invention will be described using examples of some
possible embodiments of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0033] The drawings illustrate a keyboard of the type that is
useful, for example, in a mobile device or any other electronic
device including switches and a keyboard. The mobile device could
be a mobile phone, a communication device, an electronic notebook,
a palm computer or a laptop computer etc.
[0034] The keyboard includes a rigid base member 1, which may be,
for example, the base material of a printed circuit board or a
printed wiring board, typically of dielectric material. It is
dimensionally substantially stable and may vary in thickness so
long as it retains its shape and provides a firm support. The base
member 1 includes electrical circuitry structures on its surface,
which structures define a plurality of connection zones 2 on the
first surface 1a. The electrical circuitry structures of the base
member 1 also comprise one or more dielectric layers 3, on which
the required conductive paths are located.
[0035] The keyboard also includes a dome sheet 4 covering said base
member 1, as illustrated in FIG. 2. The dome sheet 4 includes a
plurality of flexible, resilient domes 5. These domes 5 are aligned
with the connection zones 2 on the first surface 1a of the base
member 1. In one embodiment the underside of each of said domes 5
includes a conductive surface, which is capable of completing an
electrical connection at said connection zone 2 when said dome is
deflected downwardly against said circuitry structures. In
addition, it is also possible to use other connection principles,
such as, for example a capacitive principle.
[0036] The surface 1a of the base member 1 includes a plurality of
grooves 6. These grooves 6 form closed air tunnels together with
the dome sheet 4. These air tunnels connect at least two domes 5
together in such a manner that air movement between said domes
becomes possible. The domes 5 are interconnected together in order
to provide a pathway for air movement when one of the domes 5 is
depressed or collapsed toward a respective connection zone 2, as
described in more detail hereafter. Each connection zone 2 on the
base member 1 communicates with at least one such groove 6. If
desired, all of the grooves 6 and/or the air tunnels may
interconnect with each other and/or with all of the domes 5. The
grooves 6 may have varying configurations so long as they are
capable of allowing air to move therethrough when a dome 5 is
depressed. The air tunnels can be between two or more domes 5, but
they do not necessarily have to connect all the domes together. The
domes 5 on a printed wiring board can form several separate groups
connected by tunnels. Thus, the planning of a printed wiring board
is easier than when all the domes 5 should be connected to each
other with tunnels.
[0037] It should be noted that FIG. 1 shows the base member 1 only
in a partial figure and the curved line does not depict the edge of
said base member. Therefore, the grooves 6 do not reach up to the
edges of the base member 1 and do not communicate with the outside
atmosphere, but remain sealed inside the base member 1 area.
[0038] According to one embodiment of the invention, all connection
zones 2 are communicating with each other with the net of the air
tunnels when there is no venting to the atmosphere, so that the air
from one of the connection zones can be adequately dispersed when
such switch is actuated by pressing the dome downwardly. Of course,
by making the volume of each air tunnel greater, it is easier to
alleviate the extent of air compression when a single switch is
actuated. As another alternative, a larger chamber may be provided
in the base member 1, into which air may be forced when a switch is
actuated.
[0039] As illustrated in the drawings, the grooves 6 are provided
in the upper surface 1a of the base member 1. In this example, the
grooves are arranged on a coating layer 3, 7 of the surface 1a.
These grooves 6 can be made by, for example, leaving the solder
mask 7 and/or one layer 3 of copper out of the groove position. The
base member 1, such as a printed circuit board or a printed wiring
board, comprises at least one thin dielectric layer 3, on which the
required conductive paths are located. The thickness of the layer 3
may vary. FIG. 2 illustrates an embodiment of the keyboard of the
invention, which includes the grooves 6 made by leaving the solder
mask 7 out of the groove position. FIG. 3 illustrates another
embodiment of the invention, which includes the grooves 6 made by
leaving the solder mask 7 and one layer 3 of copper out of the
groove position. By means of this invention, it is possible to get
the running change faster into use in production and it is also
possible to save expenses because the air tunnel can now be made
with normal printed circuit board or printed wiring board process,
which does not cause any extra expenses. These processes are, for
example, exposure, etching, milling, depositing, evaporation and
etc.
[0040] According to the invention, the grooves 6 can be formed on
any layer processed on the actual base member 1, which layer can be
processed by means of the above-mentioned processes or other
processes for printed wiring board. Thus, the layers can be the
above-mentioned solder mask 7 or copper layers, or some other
layers, such as, for example, lacquer layers or locally applied
solder layers. All these layers are a part of the electrical
circuitry structures of the invention.
[0041] The grooves 6 can also be made in other coating layers 3, 7
than in the previous examples, as illustrated in FIGS. 2 and 3. The
grooves 6 may be entirely on one layer or on several layers. If
necessary, the thickness of the layer, such as, for example copper,
can be adjusted in order to reach the correct depth of the
grooves.
[0042] The thickness and other dimensions of the layer 3 and the
solder mask 7 and/or other coating layers in the figures do not
necessarily correspond to the situation in reality. Usually these
regions are very thin, but by drawing the regions thicker in the
figures the invention can be understood better.
[0043] Overlying the base member 1, a spacer member may be
included. The spacer member is optional. Its presence is preferred,
however, because it increases the distance the dome 5 can travel as
it is being depressed or collapsed. This provides a better "feel"
to the key being operated. The spacer member is preferably in the
form of a sheet having a uniform thickness and having openings or
cut-outs in a pattern that corresponds to the locations of the
connection zones 2. The spacer member is preferably a dielectric
material. A typical spacer member is polyester film (which may be
rigid or flexible). Alternatively, the spacer member may be
conductive so long as it is electrically insulated from the printed
circuitry.
[0044] Positioned over the base member 1 (or in some embodiments
over the spacer member) is the dome sheet 4. This dome sheet 4
includes a pattern of raised domes 5, which are aligned with the
connection zones 2 on the base member 1. When the dome sheet 4 is
dielectric (e.g. plastic) material, the bottom surface of each dome
5 includes a thin conductive layer or coating. For example, the
layer may comprise a conductive ink or conductive particles in a
polymerized coating. The dome sheet 4 may comprise a thin metal
sheet (e.g., cold rolled stainless steel). As another alternative,
strips may be provided, which each include a plurality of domes
5.
[0045] The dome sheet 4 is flexible and resilient so that each dome
5 can be downwardly depressed or collapsed by means of finger
pressure (arrow 8) and will then return to its original shape and
position when the finger pressure is released. The size and shape
of each dome 5 is often substantially the same. Other sizes and
shapes may, of course, be used in this invention.
[0046] When finger pressure (arrow 8) is used to depress or
collapse a dome 5 (e.g. as illustrated in FIG. 4), the underside
part of the dome comes into contact with the base member 1 at a
connection zone 2. At the same time the air (arrow 9) present under
dome 5 is forced into an air tunnel (groove 6). This allows the air
(arrow 9) to dissipate through the air tunnel system. If desired, a
vent aperture communicating between the air tunnel and the
atmosphere may also be included. This is not required, however, and
could allow dust or/and moisture to enter the keyboard.
[0047] The dome sheet 4 may be bonded to the top of the base member
1 (or to the top of the spacer member, if present) or it may be
clamped in place.
[0048] The mobile device could be a mobile phone, a communication
device, an electronic notebook, a palm computer or a laptop
computer etc. FIG. 5 shows a mobile phone comprising a keyboard 10,
which keyboard has been presented above.
[0049] By combining, in various ways, the modes and structures
disclosed in connection with the different embodiments of the
invention presented above, it is possible to produce various
embodiments of the invention in accordance with the spirit of the
invention. Therefore, the above-presented examples must not be
interpreted as restrictive to the invention, but the embodiments of
the invention may be freely varied within the scope of the
inventive features presented in the claims hereinbelow.
* * * * *